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The automatic defrost system of Kenmore/Whirlpool side-by-side refrigerators consists of a heating element, defrost thermostat and a defrost timer. The defrost timer is the brain of the automatic defrost system. Once in every 24-hour period it disconnects the power to the hermetically sealed compressor/motor and supplies power to the defrost heating element. The defrost thermostat keeps the temperature in the freezer compartment from exceeding a preset level of 55 degrees. Checking and replacing the defrost timer in your Kenmore side-by-side refrigerator could save you a $100 to $200 service call.

1

Locate the defrost timer. Depending on the model refrigerator that you have, the defrost timer may be located behind the temperature-control panel inside the refrigerator's cabinet, underneath the refrigerator in the compressor compartment or behind the kick-plate below the doors. Turn the timer shaft clockwise with the flat-blade screwdriver until the compressor stops, and then listen for a hissing or popping sound from the backside of the freezer compartment. A hissing and/or popping sound indicates that the timer is supplying power to the defrost heating element and that the heating element and thermostat are working properly.

2

Unplug the refrigerator's power cord from the wall receptacle. Remove the defrost timer from its mounting by removing the two machine screws securing it in place. Before disconnecting the wires from the timer, label them with their terminal numbers or letters so you can replace them in their proper order. Masking tape and a sharp-tipped felt-tipped marker works well here.

3

Set the function switch on your digital multimeter to its R X 1 setting. Touch one of the probes to the “C” or “3” terminal on the timer and the other probe to the “1” terminal. The meter's LCD should display a reading of “0.000” or some small number if the timer motor is good. A reading of “O.L.” indicates a bad timer motor, and you need to replace the timer. With the test probes clipped to the remaining two terminals, the meter display should switch from “O.L.” to “0.000” and back as you rotate the shaft through 360 degrees if the heater contacts are opening and closing properly. If the meter displays a constant “O.L.” or “0.000” through 360 degrees of rotation, the timer is bad and needs to be replaced. Take the old timer to the appliance parts store to get the proper replacement.

About the Author

Based in Colorado Springs, Colo., Jerry Walch has been writing articles for the DIY market since 1974. His work has appeared in “Family Handyman” magazine, “Popular Science,” "Popular Mechanics," “Handy” and other publications. Walch spent 40 years working in the electrical trades and holds an Associate of Applied Science in applied electrical engineering technology from Alvin Junior College.